The Ebola epidemic that has killed more than 1,500 people across West Africa spread to a fifth country in the region on Friday with the first confirmed case of the deadly virus in Senegal.

The case marks the first time a new country has been hit by the outbreak since July and comes a day after the World Health Organization warned the number of infections is increasing rapidly.

Senegal's health ministry said the patient is a young Guinean man who was immediately quarantined at a Dakar hospital, where he is in "satisfactory condition."

The man is believed to have been infected in Guinea's capital Conakry, and may have traveled to Senegal before Dakar closed its land border with Guinea on Aug. 21.

New figures released by the WHO on Thursday revealed the massive scale of the crisis, which it said indicated a "rapid increase still in the intensity of transmission" that could cost at least $490 million to tackle.

In a sign that affected countries are struggling to stop its spread, the UN agency said the number of cases could exceed 20,000 before the epidemic is brought under control.

Never before has there been an Ebola outbreak so large, nor has the virus, which was first detected in 1976, ever infected people in West Africa until now.

As of Aug. 26, 1,552 people had been confirmed dead from Ebola in four countries: Sierra Leone, Liberia, Guinea and Nigeria.

Liberia was the worst affected with 694 deaths; 422 people have died in Sierra Leone; and 430 in Guinea, where the virus emerged at the start of the year. Nigeria has now recorded six deaths.

The Democratic Republic of Congo has also confirmed two cases of Ebola, but officials there insist it is unconnected to the current outbreak in West Africa.